List the requirements to connect two different networks (Ethernet and Token ring) in the lower layers?

Ethernet and Token Ring are different layer 2 protocols. They are not compatible with each other. A computer with an ethernet NIC could not directly communicate with a computer that has a token ring NIC. You would have to have a gateway (router) in between these computers that has an ethernet and token ring interface. The gateway would be responsible for translating between the two.

No, because you would have these two types of nodes on the same physical link. In the case of a token ring network, two token ring devices would not be able to communicate at the same time. The host that holds the "token" is the one that can access the network. The token is passed from host to host. In another thread you had, you asked about ethernet and the concept of CSMA-CD was brought up. In token ring, you do not require CSMA-CD because there are no collisions in token ring. There are no collisions, because you cannot access the network unless you have the token. Only one host can have the token at one time.